OK, let's work through this together. We're starting with 921 and we're going to multiply it by 456, which means we add 921 to itself 456 times.
Step 1: 0 + 921 = 921
Step 2: 921 + 921 = 1842
Step 3: 1842 + 921 = 2763
Step 4: 2763 + 921 = 3684
Step 5: 3684 + 921 = 4605
Step 6: 4605 + 921 = 5526
Step 7: 5526 + 921 = 6447
Step 8: 6447 + 921 = 7368
Step 9: 7368 + 921 = 8289
Step 10: 8289 + 921 = 9210
Step 11: 9210 + 921 = 10131
Step 12: 10131 + 921 = 11052
Step 13: 11052 + 921 = 11973
Step 14: 11973 + 921 = 12894
Step 15: 12894 + 921 = 13815
Step 16: 13815 + 921 = 14736
Step 17: 14736 + 921 = 15657
Step 18: 15657 + 921 = 16578
Step 19: 16578 + 921 = 17499
Step 20: 17499 + 921 = 18420
Step 21: 18420 + 921 = 19341
Step 22: 19341 + 921 = 20262
Step 23: 20262 + 921 = 21183
Step 24: 21183 + 921 = 22104
Step 25: 22104 + 921 = 23025
Step 26: 23025 + 921 = 23946
Step 27: 23946 + 921 = 24867
Step 28: 24867 + 921 = 25788
Step 29: 25788 + 921 = 26709
Step 30: 26709 + 921 = 27630
Step 31: 27630 + 921 = 28551
Step 32: 28551 + 921 = 29472
Step 33: 29472 + 921 = 30393
Step 34: 30393 + 921 = 31314
Step 35: 31314 + 921 = 32235
Step 36: 32235 + 921 = 33156
Step 37: 33156 + 921 = 34077
Step 38: 34077 + 921 = 34998
Step 39: 34998 + 921 = 35919
Step 40: 35919 + 921 = 36840
Step 41: 36840 + 921 = 37761
Step 42: 37761 + 921 = 38682
Step 43: 38682 + 921 = 39603
Step 44: 39603 + 921 = 40524
Step 45: 40524 + 921 = 41445
Step 46: 41445 + 921 = 42366
Step 47: 42366 + 921 = 43287
Step 48: 43287 + 921 = 44208
Step 49: 44208 + 921 = 45129
Step 50: 45129 + 921 = 46050
Step 51: 46050 + 921 = 46971
Step 52: 46971 + 921 = 47892
Step 53: 47892 + 921 = 48813
Step 54: 48813 + 921 = 49734
Step 55: 49734 + 921 = 50655
Step 56: 50655 + 921 = 51576
Step 57: 51576 + 921 = 52497
Step 58: 52497 + 921 = 53418
Step 59: 53418 + 921 = 54339
Step 60: 54339 + 921 = 55260
Step 61: 55260 + 921 = 56181
Step 62: 56181 + 921 = 57102
Step 63: 57102 + 921 = 58023
Step 64: 58023 + 921 = 58944
Step 65: 58944 + 921 = 59865
Step 66: 59865 + 921 = 60786
Step 67: 60786 + 921 = 61707
Step 68: 61707 + 921 = 62628
Step 69: 62628 + 921 = 63549
Step 70: 63549 + 921 = 64470
Step 71: 64470 + 921 = 65391
Step 72: 65391 + 921 = 66312
Step 73: 66312 + 921 = 67233
Step 74: 67233 + 921 = 68154
Step 75: 68154 + 921 = 69075
Step 76: 69075 + 921 = 69996
Step 77: 69996 + 921 = 70917
Step 78: 70917 + 921 = 71838
Step 79: 71838 + 921 = 72759
Step 80: 72759 + 921 = 73680
Step 81: 73680 + 921 = 74601
Step 82: 74601 + 921 = 75522
Step 83: 75522 + 921 = 76443
Step 84: 76443 + 921 = 77364
Step 85: 77364 + 921 = 78285
Step 86: 78285 + 921 = 79206
Step 87: 79206 + 921 = 80127
Step 88: 80127 + 921 = 81048
Step 89: 81048 + 921 = 81969
Step 90: 81969 + 921 = 82890
Step 91: 82890 + 921 = 83811
Step 92: 83811 + 921 = 84732
Step 93: 84732 + 921 = 85653
Step 94: 85653 + 921 = 86574
Step 95: 86574 + 921 = 87495
Step 96: 87495 + 921 = 88416
Step 97: 88416 + 921 = 89337
Step 98: 89337 + 921 = 90258
Step 99: 90258 + 921 = 91179
Step 100: 91179 + 921 = 92100
Step 101: 92100 + 921 = 93021
Step 102: 93021 + 921 = 93942
Step 103: 93942 + 921 = 94863
Step 104: 94863 + 921 = 95784
Step 105: 95784 + 921 = 96705
Step 106: 96705 + 921 = 97626
Step 107: 97626 + 921 = 98547
Step 108: 98547 + 921 = 99468
Step 109: 99468 + 921 = 100389
Step 110: 100389 + 921 = 101310
Step 111: 101310 + 921 = 102231
Step 112: 102231 + 921 = 103152
Step 113: 103152 + 921 = 104073
Step 114: 104073 + 921 = 104994
Step 115: 104994 + 921 = 105915
Step 116: 105915 + 921 = 106836
Step 117: 106836 + 921 = 107757
Step 118: 107757 + 921 = 108678
Step 119: 108678 + 921 = 109599
Step 120: 109599 + 921 = 110520
Step 121: 110520 + 921 = 111441
Step 122: 111441 + 921 = 112362
Step 123: 112362 + 921 = 113283
Step 124: 113283 + 921 = 114204
Step 125: 114204 + 921 = 115125
Step 126: 115125 + 921 = 116046
Step 127: 116046 + 921 = 116967
Step 128: 116967 + 921 = 117888
Step 129: 117888 + 921 = 118809
Step 130: 118809 + 921 = 119730
Step 131: 119730 + 921 = 120651
Step 132: 120651 + 921 = 121572
Step 133: 121572 + 921 = 122493
Step 134: 122493 + 921 = 123414
Step 135: 123414 + 921 = 124335
Step 136: 124335 + 921 = 125256
Step 137: 125256 + 921 = 126177
Step 138: 126177 + 921 = 127098
Step 139: 127098 + 921 = 128019
Step 140: 128019 + 921 = 128940
Step 141: 128940 + 921 = 129861
Step 142: 129861 + 921 = 130782
Step 143: 130782 + 921 = 131703
Step 144: 131703 + 921 = 132624
Step 145: 132624 + 921 = 133545
Step 146: 133545 + 921 = 134466
Step 147: 134466 + 921 = 135387
Step 148: 135387 + 921 = 136308
Step 149: 136308 + 921 = 137229
Step 150: 137229 + 921 = 138150
Step 151: 138150 + 921 = 139071
Step 152: 139071 + 921 = 139992
Step 153: 139992 + 921 = 140913
Step 154: 140913 + 921 = 141834
Step 155: 141834 + 921 = 142755
Step 156: 142755 + 921 = 143676
Step 157: 143676 + 921 = 144597
Step 158: 144597 + 921 = 145518
Step 159: 145518 + 921 = 146439
Step 160: 146439 + 921 = 147360
Step 161: 147360 + 921 = 148281
Step 162: 148281 + 921 = 149202
Step 163: 149202 + 921 = 150123
Step 164: 150123 + 921 = 151044
Step 165: 151044 + 921 = 151965
Step 166: 151965 + 921 = 152886
Step 167: 152886 + 921 = 153807
Step 168: 153807 + 921 = 154728
Step 169: 154728 + 921 = 155649
Step 170: 155649 + 921 = 156570
Step 171: 156570 + 921 = 157491
Step 172: 157491 + 921 = 158412
Step 173: 158412 + 921 = 159333
Step 174: 159333 + 921 = 160254
Step 175: 160254 + 921 = 161175
Step 176: 161175 + 921 = 162096
Step 177: 162096 + 921 = 163017
Step 178: 163017 + 921 = 163938
Step 179: 163938 + 921 = 164859
Step 180: 164859 + 921 = 165780
Step 181: 165780 + 921 = 166701
Step 182: 166701 + 921 = 167622
Step 183: 167622 + 921 = 168543
Step 184: 168543 + 921 = 169464
Step 185: 169464 + 921 = 170385
Step 186: 170385 + 921 = 171306
Step 187: 171306 + 921 = 172227
Step 188: 172227 + 921 = 173148
Step 189: 173148 + 921 = 174069
Step 190: 174069 + 921 = 174990
Step 191: 174990 + 921 = 175911
Step 192: 175911 + 921 = 176832
Step 193: 176832 + 921 = 177753
Step 194: 177753 + 921 = 178674
Step 195: 178674 + 921 = 179595
Step 196: 179595 + 921 = 180516
Step 197: 180516 + 921 = 181437
Step 198: 181437 + 921 = 182358
Step 199: 182358 + 921 = 183279
Step 200: 183279 + 921 = 184200
Step 201: 184200 + 921 = 185121
Step 202: 185121 + 921 = 186042
Step 203: 186042 + 921 = 186963
Step 204: 186963 + 921 = 187884
Step 205: 187884 + 921 = 188805
Step 206: 188805 + 921 = 189726
Step 207: 189726 + 921 = 190647
Step 208: 190647 + 921 = 191568
Step 209: 191568 + 921 = 192489
Step 210: 192489 + 921 = 193410
Step 211: 193410 + 921 = 194331
Step 212: 194331 + 921 = 195252
Step 213: 195252 + 921 = 196173
Step 214: 196173 + 921 = 197094
Step 215: 197094 + 921 = 198015
Step 216: 198015 + 921 = 198936
Step 217: 198936 + 921 = 199857
Step 218: 199857 + 921 = 200778
Step 219: 200778 + 921 = 201699
Step 220: 201699 + 921 = 202620
Step 221: 202620 + 921 = 203541
Step 222: 203541 + 921 = 204462
Step 223: 204462 + 921 = 205383
Step 224: 205383 + 921 = 206304
Step 225: 206304 + 921 = 207225
Step 226: 207225 + 921 = 208146
Step 227: 208146 + 921 = 209067
Step 228: 209067 + 921 = 209988
Step 229: 209988 + 921 = 210909
Step 230: 210909 + 921 = 211830
Step 231: 211830 + 921 = 212751
Step 232: 212751 + 921 = 213672
Step 233: 213672 + 921 = 214593
Step 234: 214593 + 921 = 215514
Step 235: 215514 + 921 = 216435
Step 236: 216435 + 921 = 217356
Step 237: 217356 + 921 = 218277
Step 238: 218277 + 921 = 219198
Step 239: 219198 + 921 = 220119
Step 240: 220119 + 921 = 221040
Step 241: 221040 + 921 = 221961
Step 242: 221961 + 921 = 222882
Step 243: 222882 + 921 = 223803
Step 244: 223803 + 921 = 224724
Step 245: 224724 + 921 = 225645
Step 246: 225645 + 921 = 226566
Step 247: 226566 + 921 = 227487
Step 248: 227487 + 921 = 228408
Step 249: 228408 + 921 = 229329
Step 250: 229329 + 921 = 230250
Step 251: 230250 + 921 = 231171
Step 252: 231171 + 921 = 232092
Step 253: 232092 + 921 = 233013
Step 254: 233013 + 921 = 233934
Step 255: 233934 + 921 = 234855
Step 256: 234855 + 921 = 235776
Step 257: 235776 + 921 = 236697
Step 258: 236697 + 921 = 237618
Step 259: 237618 + 921 = 238539
Step 260: 238539 + 921 = 239460
Step 261: 239460 + 921 = 240381
Step 262: 240381 + 921 = 241302
Step 263: 241302 + 921 = 242223
Step 264: 242223 + 921 = 243144
Step 265: 243144 + 921 = 244065
Step 266: 244065 + 921 = 244986
Step 267: 244986 + 921 = 245907
Step 268: 245907 + 921 = 246828
Step 269: 246828 + 921 = 247749
Step 270: 247749 + 921 = 248670
Step 271: 248670 + 921 = 249591
Step 272: 249591 + 921 = 250512
Step 273: 250512 + 921 = 251433
Step 274: 251433 + 921 = 252354
Step 275: 252354 + 921 = 253275
Step 276: 253275 + 921 = 254196
Step 277: 254196 + 921 = 255117
Step 278: 255117 + 921 = 256038
Step 279: 256038 + 921 = 256959
Step 280: 256959 + 921 = 257880
Step 281: 257880 + 921 = 258801
Step 282: 258801 + 921 = 259722
Step 283: 259722 + 921 = 260643
Step 284: 260643 + 921 = 261564
Step 285: 261564 + 921 = 262485
Step 286: 262485 + 921 = 263406
Step 287: 263406 + 921 = 264327
Step 288: 264327 + 921 = 265248
Step 289: 265248 + 921 = 266169
Step 290: 266169 + 921 = 267090
Step 291: 267090 + 921 = 268011
Step 292: 268011 + 921 = 268932
Step 293: 268932 + 921 = 269853
Step 294: 269853 + 921 = 270774
Step 295: 270774 + 921 = 271695
Step 296: 271695 + 921 = 272616
Step 297: 272616 + 921 = 273537
Step 298: 273537 + 921 = 274458
Step 299: 274458 + 921 = 275379
Step 300: 275379 + 921 = 276300
Step 301: 276300 + 921 = 277221
Step 302: 277221 + 921 = 278142
Step 303: 278142 + 921 = 279063
Step 304: 279063 + 921 = 279984
Step 305: 279984 + 921 = 280905
Step 306: 280905 + 921 = 281826
Step 307: 281826 + 921 = 282747
Step 308: 282747 + 921 = 283668
Step 309: 283668 + 921 = 284589
Step 310: 284589 + 921 = 285510
Step 311: 285510 + 921 = 286431
Step 312: 286431 + 921 = 287352
Step 313: 287352 + 921 = 288273
Step 314: 288273 + 921 = 289194
Step 315: 289194 + 921 = 290115
Step 316: 290115 + 921 = 291036
Step 317: 291036 + 921 = 291957
Step 318: 291957 + 921 = 292878
Step 319: 292878 + 921 = 293799
Step 320: 293799 + 921 = 294720
Step 321: 294720 + 921 = 295641
Step 322: 295641 + 921 = 296562
Step 323: 296562 + 921 = 297483
Step 324: 297483 + 921 = 298404
Step 325: 298404 + 921 = 299325
Step 326: 299325 + 921 = 300246
Step 327: 300246 + 921 = 301167
Step 328: 301167 + 921 = 302088
Step 329: 302088 + 921 = 303009
Step 330: 303009 + 921 = 303930
Step 331: 303930 + 921 = 304851
Step 332: 304851 + 921 = 305772
Step 333: 305772 + 921 = 306693
Step 334: 306693 + 921 = 307614
Step 335: 307614 + 921 = 308535
Step 336: 308535 + 921 = 309456
Step 337: 309456 + 921 = 310377
Step 338: 310377 + 921 = 311298
Step 339: 311298 + 921 = 312219
Step 340: 312219 + 921 = 313140
Step 341: 313140 + 921 = 314061
Step 342: 314061 + 921 = 314982
Step 343: 314982 + 921 = 315903
Step 344: 315903 + 921 = 316824
Step 345: 316824 + 921 = 317745
Step 346: 317745 + 921 = 318666
Step 347: 318666 + 921 = 319587
Step 348: 319587 + 921 = 320508
Step 349: 320508 + 921 = 321429
Step 350: 321429 + 921 = 322350
Step 351: 322350 + 921 = 323271
Step 352: 323271 + 921 = 324192
Step 353: 324192 + 921 = 325113
Step 354: 325113 + 921 = 326034
Step 355: 326034 + 921 = 326955
Step 356: 326955 + 921 = 327876
Step 357: 327876 + 921 = 328797
Step 358: 328797 + 921 = 329718
Step 359: 329718 + 921 = 330639
Step 360: 330639 + 921 = 331560
Step 361: 331560 + 921 = 332481
Step 362: 332481 + 921 = 333402
Step 363: 333402 + 921 = 334323
Step 364: 334323 + 921 = 335244
Step 365: 335244 + 921 = 336165
Step 366: 336165 + 921 = 337086
Step 367: 337086 + 921 = 338007
Step 368: 338007 + 921 = 338928
Step 369: 338928 + 921 = 339849
Step 370: 339849 + 921 = 340770
Step 371: 340770 + 921 = 341691
Step 372: 341691 + 921 = 342612
Step 373: 342612 + 921 = 343533
Step 374: 343533 + 921 = 344454
Step 375: 344454 + 921 = 345375
Step 376: 345375 + 921 = 346296
Step 377: 346296 + 921 = 347217
Step 378: 347217 + 921 = 348138
Step 379: 348138 + 921 = 349059
Step 380: 349059 + 921 = 349980
Step 381: 349980 + 921 = 350901
Step 382: 350901 + 921 = 351822
Step 383: 351822 + 921 = 352743
Step 384: 352743 + 921 = 353664
Step 385: 353664 + 921 = 354585
Step 386: 354585 + 921 = 355506
Step 387: 355506 + 921 = 356427
Step 388: 356427 + 921 = 357348
Step 389: 357348 + 921 = 358269
Step 390: 358269 + 921 = 359190
Step 391: 359190 + 921 = 360111
Step 392: 360111 + 921 = 361032
Step 393: 361032 + 921 = 361953
Step 394: 361953 + 921 = 362874
Step 395: 362874 + 921 = 363795
Step 396: 363795 + 921 = 364716
Step 397: 364716 + 921 = 365637
Step 398: 365637 + 921 = 366558
Step 399: 366558 + 921 = 367479
Step 400: 367479 + 921 = 368400
Step 401: 368400 + 921 = 369321
Step 402: 369321 + 921 = 370242
Step 403: 370242 + 921 = 371163
Step 404: 371163 + 921 = 372084
Step 405: 372084 + 921 = 373005
Step 406: 373005 + 921 = 373926
Step 407: 373926 + 921 = 374847
Step 408: 374847 + 921 = 375768
Step 409: 375768 + 921 = 376689
Step 410: 376689 + 921 = 377610
Step 411: 377610 + 921 = 378531
Step 412: 378531 + 921 = 379452
Step 413: 379452 + 921 = 380373
Step 414: 380373 + 921 = 381294
Step 415: 381294 + 921 = 382215
Step 416: 382215 + 921 = 383136
Step 417: 383136 + 921 = 384057
Step 418: 384057 + 921 = 384978
Step 419: 384978 + 921 = 385899
Step 420: 385899 + 921 = 386820
Step 421: 386820 + 921 = 387741
Step 422: 387741 + 921 = 388662
Step 423: 388662 + 921 = 389583
Step 424: 389583 + 921 = 390504
Step 425: 390504 + 921 = 391425
Step 426: 391425 + 921 = 392346
Step 427: 392346 + 921 = 393267
Step 428: 393267 + 921 = 394188
Step 429: 394188 + 921 = 395109
Step 430: 395109 + 921 = 396030
Step 431: 396030 + 921 = 396951
Step 432: 396951 + 921 = 397872
Step 433: 397872 + 921 = 398793
Step 434: 398793 + 921 = 399714
Step 435: 399714 + 921 = 400635
Step 436: 400635 + 921 = 401556
Step 437: 401556 + 921 = 402477
Step 438: 402477 + 921 = 403398
Step 439: 403398 + 921 = 404319
Step 440: 404319 + 921 = 405240
Step 441: 405240 + 921 = 406161
Step 442: 406161 + 921 = 407082
Step 443: 407082 + 921 = 408003
Step 444: 408003 + 921 = 408924
Step 445: 408924 + 921 = 409845
Step 446: 409845 + 921 = 410766
Step 447: 410766 + 921 = 411687
Step 448: 411687 + 921 = 412608
Step 449: 412608 + 921 = 413529
Step 450: 413529 + 921 = 414450
Step 451: 414450 + 921 = 415371
Step 452: 415371 + 921 = 416292
Step 453: 416292 + 921 = 417213
Step 454: 417213 + 921 = 418134
Step 455: 418134 + 921 = 419055
Step 456: 419055 + 921 = 419976

So, 921*456 = 419976